Fire extinguisher



Feb. 22, 1955 5, E, ALLEN 2,702,600

FIRE EXTINGUISHER Filed sept. 25, A1951 2 sheets-sheet 1 BYE, H.

Feb. 22, 1955 s'. E. ALLEN FIRE EXTINGUISHER 2 Sheets-Sheet 2 Filed Sept. .25 1951 INVENTOR. 'l .Scorri/Q 5N Y B w QT 8MM A T TOR/VFY FIRE EXTINGUISHER Scott E. Allen, Verona, N. J.

Application September 25, 1951, Serial No. 248,111

Claims. (Cl. 169-31) The present invention relates to fire extinguishers and particularly to an improved liquid extinguisher having a corrosion minimizing construction.

The usual water type extinguisher is pressurized by carbon dioxide stored in a high pressure cartridge having at least its lower end immersed in the water. By reason of the use of metals of diiering composition, galvanic currents are often set up between the cartridge and the container resulting in corrosion. As the high pressure cartridge is generally made of high tensile strength steel and the container may be made of brass, stainless steel or composition material, the cartridge becomes pitted from electrolytic corrosion resulting in its lessened strength and in possible leakage of its stored pressure medium. As a result of the corrosive action, the water becomes discolored and may stain objects upon which it is discharged.

Prior attempts have been made to overcome the corrosion difficulty. United States Patent No. 1,382,619, issued in 1921, describes a compressed gas-pressurized fire extinguisher made of metal preferably coated on the inside with shellac or other material which will protect the metal against any corrosive action of the liquid in the container. United States Patent No. 1,976,056, issued in 1934, discloses a sheet metal container preferably of sheet copper tinned on the inside, obviously to prevent corrosion. United States Patent No. 1,956,744, issued in 1934, discloses a solution of the problem as follows: To prevent corrosion of the steel cartridge case and electrolytic action between the steel of the cartridge case and the inner wall surface of the tank which would result in pitting of the steel wall of the cartridge case and nally allow escapement of the carbon dioxide from the cartridge case into the tank, the enlarged portion of the cartridge case is enclosed in a lead skirt. United States Patent No.- 1,976,467, issued in 1934, solved the electrolytic corrosion problem by providing `a protecting sack of rubber to be pulled over the cartridge case.

The present invention aims to overcome the difliculties and disadvantages of prior devices byproviding in an improvement thereover of a lire extinguisher in which electrical non-conducting material is used for the support of the cartridge with respect to the container so as to prevent the ow of-galvanic currents between the cartridge and the container.

The construction is advantageous in that the cartridge may be readily removed from its support for recharging or replacementV as a non-corrosive joint is provided by contact between electrical conducting and electrical non-conductingmaterials. v

Other objects and advantages of the invention will be apparent from the following description and from the accompanying drawings, which show, by way ofexamples, embodiments of the invention.

In the drawings:

Figure l is a vertical sectional view of a fire extinguisher in accordance with the invention, the lower portion of the extinguisher being shown broken away.

Figure 2 is a partial vertical sectional view of a re extinguisher in accordance with the invention utilizing a conversion unit such as may be used to adapt a sodaacid extinguisher to a water extinguisher.

Figure 3 is a partial vertical sectional view of another extinguisher in accordance with the invention utilizing a modied conversion unit.

' Figure 4 is a partialvertical sectional view of an exnited States Patent() 2,702,600 Patented Feb. 22, 1955 tinguisher in accordance with the invention utilizing another modiiied conversion unit. r

. Referring to the drawings, there is shown in Figure 1 a lire extinguisher 1 including a container 2 for a liquid re extinguishing agent, such as water, and closed by a combination carrying member and discharge head 3. In order that the re extinguishing agent may be expelled from the container 2, a cartridge 4 of stored pressure medium is provided and supported within the container 2 by the discharge head 3 which also carries puncturing means 5 for the release of the stored pressure medium from the cartridge 4.

The container 2 may be constructed of any suitable material such as brass or stainless steel and is generally made of a strength to withstand a test pressure of 500 pounds per square inch. 1n the usual portable extinguisher the capacity of the container 2 is generally about two and one-half gallons of uid, although a container of any desired size may be used. Adjacent the top of the container 2 is an outlet elbow 6 having attached thereto one end of a conventional' h'ose 7 which may have a nozzle at its other end (not shown) for directing an is'- suing stream to a lire.

The container 2 is charged hrough a lling opening at its top denedby a ange member 9 secured to the wall of the container 2 by a welded joint 10 or Dyorher suitable means. The exterior of the ange member Y9'is threaded to receive the combination discharge head and carrying handle 3.

The material used for the construction of the combination discharge head and carrying handle 3 may be cast brass or other suitable material. A preferred form ol construction of the combination discharge head and carrying handle is described and claimed in the Frank B. Allen application, Serial No. 167,220, filed June 9, 1950, now Patent No. 2,610,693 granted September 16, 1952, although other conventional constructions may be used which are Well-known in the art.

As shown, the combination discharge head and' carrying handle 3 is provided on its lower surface with a downwardly depending portion 11 through which extend lateral venting passages `12 for the outlet ot` uid released fromrthe cartridge 4. AOn the top of the carrying handle 3 is an upwardly extending tubular extension 14 to receive the puncturing member 5. At the outer end 'of the puncturing member 5 is a cap 15 secured by a pin 16 passing through aligned apertures in the Cap 4and puncturing member. The intermediate portion of the tubular extension 14 has its passage`17 of reduced diam'-` eter to provide a bearing surface 18 to slideably receive the puncturing'member 5. vThe lower portion of the tubular extension 14 is of a diameter to receive' enlarged portion 19 of the puncturing member 5 which -is made with an annular recess 20 to receive an O-ring'gasket'zl. The lower end of the puncturing member 5'is pointedas indicated at 22.

The pressurizing medium generally used is compressed carbon dioxide stored in the cartridge'4. To provide the desired strength the cartidge 4 is preferably made of high tensile strength steel, although brass or otherV material with suiicient tensile strength' may be used'. The cartridge is tted with a closure tting 26', 'such as is disclosed and claimed in the Robert H. Hill application, Serial No. 169,490; filed lune 2l, 1950, or other conventional construction. As shown, cartridge neck 25 is threaded exteriorly to receive a closure fitting. 26. The upper edge of the neck 25 has an upwardly extending annular portion providing a seat 27 against which is positioned a frangible disc 29 secured in position by threaded engagement of a ring nut 30 withthe interior surface of the tting 26. The lower exterior surface of the tting 26 is formed with ilattened surfaces 31 or equivalent construction to be engaged by a wrench for the tightening of the tting on the cartridge 4. The upper exterior surface of the tting 26 is threaded to engage with supporting means later to be described. In order that the discharge from the cartridge 4 may be. metered, an orifice member 32 is secured within the passage in the neck 25 with the edge of the orifice member between the seat 27 and the frangible disc 29. Thek orice member 32 is disclosed and claimed in the Frank' B. Allen application, Serial No. 137,847', tiled Ianuary l0, 1950, and is made with a downwardly depending side wall 34 having a bottom surface apertured as inF dicated at 35. The length of the downwardly depending surface is suicient to provide clearance with the pointed end Y22 of the puncturingmember` 5 after it has ruptured the disc 29. The edge of the orifice member 32 is made of soft material so as to provide a seal between the seat 27 and the frangible disc 29.

The support for the cartridge 4 is electrical insulating or non-conducting means preferably in the form of a bushing member 40V adapted to be received in the open end of the downwardly depending portion 11. The bushing 40 is` preferably made of a laminated fabric base phenolic resin impregnated molded tubing which is a good insulating material and, of course, is non-corrosive. The bushing might be made of other electrical nonconducting material such as the synthetic resins, nylon, phenol-formaldehyde, urea-formaldehyde, Melamine, Teon, hard or synthetic rubber, and fiber glass, asbestos, or mica bonded with such synthetic resins, or porcelain, glass. or equivalent material. The bushing is made with its upper end of one diameter while its lower end 41 is made of reduced diameter so that the bushing may be secured in position by turning in the lower end of the depending portion 11. If desired, the depending portion 11 and the bushing 40V may be apertured to receive one or more pins 42 to prevent therotation of the bushing 40. Alternatively, longitudinally extending grooves may be made in the bushing 40 to receive projections extending inwardly from the member 11, or any other suitable equivalent construction may be used to prevent the rotation of the bushing member 40 with respect to the member 11. The internal surface of the bushing 40 is threaded to receive the closure fitting 26, a left-hand thread being used at this location while the iitting 26 is secured to the neck 25 of the cartridge 4 by the use of a right-hand thread. The threaded connection may be made tight because of the resiliency of the insulating material, thus, the threads of the cartridge are protected against corrosion. The axial length of the bushing 4 0 is such as to prevent contact between the upper end of the closure fitting 26 and the lower surface of the discharge head 3 so that electrical contact is prevented therebetween,

In the operation of the extinguisher 1 it is inverted and the cap memberstruck against a surface to push the pointed end 22 of the puncturing member 5 through the frangible disc 29 so as to release the pressurizing iiuid from cartridge 4. The pressurizing uid is metered bythe orifice member 32 and ows through the opening in the ruptured disc 29 and outwardly through the venting passages 12 to pressurize the liquid in the extinguisher to expel it through the outlet elbow 6 and discharge hose 7.

Another embodiment of the invention is shown in Figure 2 in which corresponding parts are designated by the same reference numerals as in Figures 1-4 with the addition of 200. The extinguisher 201 diiers primarily from the extinguisher 1 in that the discharge head 203 has been converted from the soda-acid type extinguisher head to a water pressurized extinguisher by the use of a conversion unit such as is described and claimed in my co-pending application, Serial No. 248,110, filed September 25, 1951. In thisl construction the conventional combination discharge head and carrying handle 203 is drilled in the center of its closure surface to receive a unitary assemblv including the puncturing means and the support for the cartridge 204. In this construction the exterior surface of the upwardlv extending portion 214 is threaded to receive a ring nut 250, a gasket 251 being interposed between the under side of the discharge head 203 and a shoulder 252 formed by the downwardly depending portion 211. In this construction the bushing member 240 is made of non-conducting electrical material as in the case of the bushing 40. Alternatively, a construction may be used in which the body of the conversion unit is made of an electrical nonconducting material of the same or equivalent material. as is used for the bushing member 240. In this event the bushing member may be made of either conducting or non-conducting material.

In Figure 3 another embodiment of the invention is illustrated in which corresponding parts are designated by the same reference numerals as in Figurev 1 with the addition of 300. However, in Figure 3 the container and cartridge have been omitted for simplicity of illustration, this construction differing primarily from that shown in Figure 2 in that the bushing 340 is made of metal while the gasket 351 and the name plate disc 354 are made of an electrical non-conducting material as previously described. The opening in the discharge head 303 is made somewhat larger than in the extinguisher shown in Figure 2 so that the packing material 351 prevents contact between the metal of the discharge head 303 and the body 314 for the puncturing member. Thus, electrical contact is prevented between the body 314 which is adapted to be in electrical contact with the iiuid container of the extinguisher and the cartridge extending into the fluid.

Still another embodiment of the invention is illustrated in Figure 4 in which corresponding parts are designated by the same reference numerals as in Figure l with the addition of 400. In this iigure as in Figure 3 the body of the container and the cartridge have been omitted for simplicity of illustration. This embodiment differs primarily from those previously described in the construction of the insulating means between the cartridge supporting bushing 440 and the discharge head 403. The puncturing member body 414 has its lower end 460 of reduced diameter and threaded on its exterior surface. An L-shaped insulating bushing 461 has both its interior and exterior surface threaded and is adapted to be received over the reduced portion 460 and to coact with a gasket 462 made of insulating material and adapted to overlie the upper surface of the bushing 440 so as to prevent electrical contact between the bushing 440 and the discharge head 403. In this construction the cartridge supporting means or bushing 440 may be made of metal with its inner surface threaded to engage with the outer threaded surface of the bushing 461.

`It is thus apparent that a lire extinguisher has been provided in which electrical non-conducting material is used for the support of the cartridge with respect to the container so as to prevent the flow of galvanic currents therebetween with the resulting hazard of pitting and weakening of the cartridge.

While the invention has been described and illustrated with reference to specific embodiments thereof, it will be understood that other embodiments will be resorted to without departing from the invention. For example, while the cartridge has been described and illustrated as provided with electrical non-conducting means between the cartridge and the discharge head and carrying handle, other constructions might be utilized in which the discharge head is insulated from the contain-er such as by providing an insulating bushing between the d-ischarge head 3 and the ange member 9 of the container, therefore, the form of the invention set out above should be considered as illustrative and not as limiting the scope of the following claims.

I claim:

1. `In a tire extinguisher of the type used for dispensing an electrically conductive fire extinguishing agent and including a metal container for the re extinguishing agent, a metal cartridge for stored pressure medium for expelling the tire extinguishing agent, and supporting means for the cartridge relative to the container positioning the lcartridge exposed to contact with the conductive re ex tinguishing agent stored in the container, the improvement wherein electrical insulating means is incorporated in at least a part of the supporting means preventing the flow of galvanic current through the supporting means, whereby corrosion of the cartridge is minimized 2. 'In la fire extinguisher of the type used for dispensing an electrically conductive fire extinguishing agent and inycluding a metal container for the fire extinguishing agent, a metal cartridge for stored pressure medium for expelling the fire extinguishing agent, a metallic closure member for the container, and supporting means for the cartridge relative to the container located on the underside of the closure member and positioning the cartridge exposed to contact with the conductive lire extinguishing agent stored in the container, the improvement wherein electrical insulating means is incorporated in at least a part of the supporting means preventing the iiow of galvanic current through the supporting means, `whereby corrosion of the cartridge is minimized.

3. =In a fire extinguisher of the type used for dispensing an electrically conductive fire extinguishing agent and including a metal container for the tire extinguishing agent, a metal cartridge for stored pressure medium for expelling the fire extinguishing agent, and supporting means for the cartridge relative to the container positioning the cartridge exposed to contact with the conductive re extinguishing agent stored in the container, the improvement wherein an electrical insulating bushing is incorporated in the supporting means preventing the flow of galvanic current through the supporting means, whereby corrosion of the cartridge is minimized.

4. In a tire extinguisher of the type used for dispensing an electrically conductivey ire extinguishing lagent and including a metal container for the re extinguishing agent, a metal cartridge for stored pressure medium for expelling the re extinguishing agent, a metallic closure member for the container, and supporting means for the cartridge relative to the container located on the underside of the closure member and positioning the c-artridge exposed to contact with the conductive re extinguishing agent stored in the container, the improvement wherein an electrical insulating bushing is incorporated in the supporting means preventing the ow of g-alvanic current through the supporting means, whereby corrosion of the cartridge is minimized.

5. A fire extinguisher comprising a metallic container yfor extinguishing uid, a metallic closure member for the container, a metallic cartridge for pressurizing fluid to expel the extinguishing uid from the container, supporting means for the cartridge separable from the closure member, the cartridge threadedly engaged with the supporting means, and insulating material positioned between the supporting means and the metallic closure member.

References Cited in the le of this patent UNITED STATES PATENTS 1,976,467 Wheeler Oct. 9, 1934 FOREIGN PATENTS 27,386 `Great Britain Sept. 2, 1909 245,999 Great Britain Jan. 21, 1926 

